Method for continuous dyeing of textile materials made from linear,aromatic polyesters



United States Patent US. Cl. 846 Claims ABSTRACT OF THE DISCLOSURE Textile materials made from linear aromatic polyesters are continuously dyed, with production of water-insoluble azo dyes thereon, by impregnating the textile material with an aqueous dispersion of a diazotizable amine and of a coupling component, subjecting the textile material to steaming or drying, then subjecting it to a dry heating treatment at a temperature between 140 C. and 230 C., and finally treating it with an aqueous solution of an acid and a salt of nitrous acid, all these operation steps being carried out in succession in a continuous manner.

-It is known that it is possible to dye textile materials made from linear, aromatic polyesters while producing water-insoluble azo dyestuffs, if a diazotizable amine and a coupling component, such as an aniline derivative and an aryl amide of the 2:3-hydroxynaphthoic acid, are applied either simultaneously or separately and if the amine is subsequently diazotized on the textile material and coupled to form the azo dyestuff. Generally the application of the dyestutf components is carried out by an exhaust process, which consists in treating the textile material for about one hour at a temperature of about 100 C. or under pressure at high tempertaures, for instance at a temperature ranging from 120 to 130 C., in an aqueous dye bath containing the dyestutf components in a dissolved or microdispersed form. Moreover, methods enabling a continuous application of the dyestuif components are also well known. Thus it is possible to impregnate the textile material separately or simultaneously with both dyestuff components which have been dissolved in an organic solvent and to then subject the impregnated textile material to a drying or steaming operation. The development of the dyeing by diazotization and coupling takes place in all these cases in a discontinuous manner, for example by treating the fabric for a long period at elevated temperatures, eg for 30 minutes at 80 C., with an aqueous bath containing sodium nitrite and an acid.

It has now been found that textile materials made from linear, aromatic polyesters can be dyed in a continuous manner, while producing water-insoluble azo dyestutfs. This new method consists in impregnating the textile material with a diazotizable amine and a coupling component which are finely divided in water, whereupon the textile material is steamed or dried and then subjected to a dry heating treatment at a temperature ranging between 140 C. and 230 C., and is finally treated with an aqueous solution of an acid and a salt of nitrous acid, all these operation steps being carried out in a continuous manner.

The expression textile material made from linear, aromatic polyesters used in this specification comprises more particularly fabrics made from polyethylene ter- 3,515,504 Patented June 2, 1970 ice ephthalate. The dyestuff components can be those used conventionally according to the methods hitherto known for the production of water-insoluble azo dyestuffs onto textile materials made from aromatic polyesters, Examples of diazotizable amines are l-aminol nitrobenzene, l-amino 2 methoxy-S-nitrobenzene, 4-amino-2'z3-dimethyl 1:1 azobenzene, 4:4-diamino-1:l'-phenylazonaphthalene, 4,4'-diamino-3:3-dirnethoxy-diphenyl and 4:4'-diamino-2:2', 5:5'-tetrachlorodiphenyl. As coupling components there may be used for example 2-methoxyanilide, Z-methylanilide, 2:5-dimethoxyanilide or 2:4-dimethoxy-S-chloranilide of 2:3-hydroxynaphthoic acid and the 4-chloranilide of 2:3-hydroxycarbazolcarboxylic acid. The required fine distribution of the dyestutf components in water can be achieved in a per se conventional manner, for instance by means of wetting agents, dispersing agents and/or dissolving assistants, such as dinaphthylmethane disulfonic acid, dodecylbenzene sulfonic acid, nonylphenol-ethylene oxide-addition compounds, ethylene glycol monoethyl ether, dimethylformamide, methacrylic acid or polyvinyl lactames. It is also possible to add the usual auxiliary agents such as pH adjusting substances, to the aqueous solutions or dispersions respectively.

The impregnation of the textile material can be effected by passing the said material through the dye liquor, preferably at room temperature (about 15 to about 30 C.), and by squeezing the same for instance by means of a padding machine, the speed of the fabric ranging between about 10 to 15 meters/minute. The steaming or drying respectively is generally carried out at a temperature of about C., the textile material being treated in this way for 1 to 5 minutes. A steaming operation of about 2 minutes has proved to be particularly advantageous. The dry heating treatment is carried out at a temperature of to 230 C. for a period of generally 30 seconds to 3 minutes and advantageously of about 2 minutes. In order to eflect the diazotization and coupling, it is possible to use a developing bath of per se conventional composition, e.g an aqueous solution of sodium nitrite and sulfuric acid. The development is advantageously carried out at about 50 to 100 C. It is a surprising fact that a period of only 1 to 5 and optionally of about 2 minutes is sufficient to cause a complete development. This surprising discovery also makes it possible to carry out the present process in a continuous manner. Finally the dyed textile material can be soaped and rinsed in the usual way and this also in a continuous manner.

If desired, also other dyestuffs, such as dispersion dyestuffs, which are stable against nitrous acid, can simultaneously be used beside the amines and coupling components yielding insoluble azo dyestuffs, when working according to the present invention.

The present new method yields excellent results, if textile materials made from linear, aromatic polyesters and more particularly polyethylene terephthalate fabrics, are dyed in this way. Compared with the methods known up to now the novel method has particularly the advantage that all operation steps can be carried out one after the other in a completely continuous manner and within a short time. In view of these facts the present novel method is extremely economical. Moreover, according to the present invention, it is unnecessary to make use of special pressure vessels, of organic solvents or swelling agents or so-called carriers respectively. Furthermore-and this is a further advantage of the present methodno subsequent washing step, e.g. with sodium dithionite, is necessary, while such a subsequent washing operation is required in most methods known up to now.

The present invention will now be described in more detail in the following example without, however, being limited thereto.

EXAMPLE Well Washed polyethylene terephthalate piece goods are padded on the foulard at room temperature by means of a dye bath containing per 1000 parts of water 35 parts of the 2-methoxyanilide of 2:3-hydroxynaphthoic acid and 35 parts of 4:4-diamino-1:1'-phenylazonaphthalence, dispersed according to the disclosure given in Swiss Pat. No. 382,338, as well as 100 parts of urea, then they are squeezed, until the water content amounts to about 80%, and subsequently steamed for 2 minutes at a temperature of 102 C. Then the textile material is subjected to a dry heating treatment for 2 minutes at a temperature of 150 C. and treated for 2 minutes at a temperature ranging from 75 to 80 C. in a developing bath containing 18 parts of concentrated sulphuric acid and 4 parts of sodium nitrite dissolved in 1000 parts of water. Finally the textile material is soaped in a boiling bath containing per 1000 parts of water 2 parts of a nonylphenol-ethylene oxideaddition product and 1 part of sodium. carbonate and then rinsed. All Working steps are carried out in a continuous Way one after the other.

When Working in this way a deep, neutral black dyeing is produced. The quality of the dyeing is equal in any respect to dyeings produced according to known methods.

If, in the above example, the Z-methoxyanilide of the 2:3-hydroxynaphthoic acid and the 4:4-diamino-1:1'- phenylazonaphthalene are replaced by corresponding quantities of the Z-ethoxyanilide of 2:3-hydroxynaphthoic acid and 2:S-dimethyl-4-aminoazobenzene, deep Bordeaux red shades, having excellent fastness properties fully comparable with dyeings produced according to known methods are obtained.

What we claim is:

1. A method for continuously dyeing textile materials made from linear, aromatic polyesters, While producing water-insoluble azo dyestulfs on the said textile material comprising impregnating the textile material with an aqueous dispersion of a diazotizable amine and of a coupling component, subjecting the textile material for a period of 1-5 minutes to drying, then subjecting it to a dry heating treatment for a period of 30 seconds to 3 minutes at a temperature between 140 C. and 230 C., and finally treating it for a period of 15 minutes at a temperature between C. and C. with an aqueous solution of sulphuric acid and an alkali nitrite to achieve diazotizing and coupling, all these operation steps being carried out in succession in a continuous manner.

2. A method according to claim 1, wherein the textile material is made of polyethylene terephthalate.

3. A method according to claim 2, wherein the diazotizable amine is selected from the group consisting of l-amino-4-nitrobenzene, 1 amino-Z-methoxy-S-nitrobenzene, 4-arnino 2':3 dimethyl-1:1-azobenzene, 4:4-diamino-1: l'-phenylazonaphthalene, 4,4 diamino-3 3-dimethoxy-diphenyl and 4:4'-diamino-2:2, 5:5-tetrachlorodiphenyl, and the coupling component is selected from the group consisting of 2-methoxyanilide, Z-methylanilide, 2:5-dimethoxyanilide and 2:4-dimethoxy-S-chloranilide of 2:3-hydroxynaphthoic acid and the 4-chloranilide of 2 :3 -hydroxycarbazolcarboxylic acid.

4. A method according to claim 2, wherein the amine is 2-methoxyanilide of 2:3-hydroxynaphthoic acid and the coupling component is 4:4-diamino-l:1'-phenylazonaphthalene.

5. A method according to claim 2, wherein the amine is Z-ethoxyam'lide of 2:3-hydroxynaphthoic acid and the coupling component is 2:5-dimethyl-4-aminoazobenzene.

References Cited UNITED STATES PATENTS 2,088,506 7/1937 Chambers 845 FOREIGN PATENTS 382,338 11/1964 Switzerland.

GEORGE F. LESMES, Primary Examiner T. I. HERBERT 111., Assistant Examiner U.S. Cl. X.R. 

